Distributed Spacecraft Path Planning and Collision Avoidance via Reciprocal Velocity Obstacle Approach

This paper presents the development of a combined linear quadratic regulation and reciprocal velocity obstacle (LQR/RVO) control algorithm for multiple satellites during close proximity operations. The linear quadratic regulator (LQR) control effort drives the spacecraft towards their target position while the reciprocal velocity obstacle (RVO) provides collision avoidance capabilities. Each spacecraft maneuvers independently, without explicit communication or knowledge in term of collision avoidance decision making of the other spacecraft in the formation. To assess the performance of this novel controller different test cases are implemented. Numerical results show that this method guarantees safe and collision-free maneuvers for all the satellites in the formation and the control performance is presented in term of Δv and fuel consumption

Safe Positively Invariant Sets for Spacecraft Obstacle Avoidance

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140643/1/1.g000115.pd

Data systems concepts for space systems, phase 1

Deviations from the traditional spacecraft data systems were studied. A data system architecture was developed from the top down

Control of spacecraft in proximity orbits

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2007.Includes bibliographical references (p. 175-189).Formation flying of spacecraft and autonomous rendezvous and docking of spacecraft are two missions in which satellites operate in close proximity and their relative trajectories are critically important. Both classes of missions rely on accurate dynamics models for fuel minimization and observance of strict constraints for preventing collisions and achieving mission objectives. This thesis presents improvements to spacecraft dynamics modeling, orbit initialization procedures, and failsafe trajectory design that improve the feasibility and chances of success for future proximity operations. This includes the derivation of a new set of relative linearized orbital dynamics incorporating the effects of Earth's oblateness. These dynamics are embedded in a model predictive controller, enabling LP-based MPC formulations for large baseline formations in highly elliptic orbits. An initialization algorithm is developed that uses the new dynamics to optimize multiple objectives (drift and fuel usage minimization, geometry) over science-relevant time frames, improving previous J2-invariant initialization techniques which only considered infinite-horizon secular drift. The trajectory planning algorithm is used to design spacecraft rendezvous paths that observe realistic constraints on thruster usage and approach path.(cont.) The paths are fuel-optimized and further constrained to be safe (i.e., avoid collisions) in the presence of many possible system failures, an enhancement over previous guaranteed-safe rendezvous methods, which did not minimize fuel use. The fuel costs of imposing safety as a constraint on trajectory design are determined to be low compared to standard approaches and a stochastic analysis demonstrates that both active and passive forms of the safe rendezvous algorithm substantially decrease the likelihood of system failures resulting in collisions. The effectiveness of the new controller/dynamics combination is demonstrated in high fidelity multi-week simulations. An optimized safe rendezvous trajectory was demonstrated on a hardware testbed aboard the International Space Station.by Louis Scott Breger.Ph.D

Platooning-based control techniques in transportation and logistic

This thesis explores the integration of autonomous vehicle technology with smart manufacturing systems. At first, essential control methods for autonomous vehicles, including Linear Matrix Inequalities (LMIs), Linear Quadratic Regulation (LQR)/Linear Quadratic Tracking (LQT), PID controllers, and dynamic control logic via flowcharts, are examined. These techniques are adapted for platooning to enhance coordination, safety, and efficiency within vehicle fleets, and various scenarios are analyzed to confirm their effectiveness in achieving predetermined performance goals such as inter-vehicle distance and fuel consumption. A first approach on simplified hardware, yet realistic to model the vehicle's behavior, is treated to further prove the theoretical results. Subsequently, performance improvement in smart manufacturing systems (SMS) is treated. The focus is placed on offline and online scheduling techniques exploiting Mixed Integer Linear Programming (MILP) to model the shop floor and Model Predictive Control (MPC) to adapt scheduling to unforeseen events, in order to understand how optimization algorithms and decision-making frameworks can transform resource allocation and production processes, ultimately improving manufacturing efficiency. In the final part of the work, platooning techniques are employed within SMS. Autonomous Guided Vehicles (AGVs) are reimagined as autonomous vehicles, grouping them within platoon formations according to different criteria, and controlled to avoid collisions while carrying out production orders. This strategic integration applies platooning principles to transform AGV logistics within the SMS. The impact of AGV platooning on key performance metrics, such as makespan, is devised, providing insights into optimizing manufacturing processes. Throughout this work, various research fields are examined, with intersecting future technologies from precise control in autonomous vehicles to the coordination of manufacturing resources. This thesis provides a comprehensive view of how optimization and automation can reshape efficiency and productivity not only in the domain of autonomous vehicles but also in manufacturing

Aeronautical Engineering: A special bibliography with indexes, supplement 64, December 1975

This bibliography lists 288 reports, articles, and other documents introduced into the NASA scientific and technical information system in November 1975

Spacecraft nonlinear attitude control with bounded control input

The research in this thesis deals with nonlinear control of spacecraft attitude stabilization and tracking manoeuvres and addresses the issue of control toque saturation on a priori basis. The cascaded structure of spacecraft attitude kinematics and dynamics makes the method of integrator backstepping preferred scheme for the spacecraft nonlinear attitude control. However, the conventional backstepping control design method may result in excessive control torque beyond the saturation bound of the actuators. While remaining within the framework of conventional backstepping control design, the present work proposes the formulation of analytical bounds for the control torque components as functions of the initial attitude and angular velocity errors and the gains involved in the control design procedure. The said analytical bounds have been shown to be useful for tuning the gains in a way that the guaranteed maximum torque upper bound lies within the capability of the actuator and, hence, addressing the issue of control input saturation. Conditions have also been developed as well as the generalization of the said analytical bounds which allow for the tuning of the control gains to guarantee prescribed stability with the additional aim that the control action avoids reaching saturation while anticipating the presence of bounded external disturbance torque and uncertainties in the spacecraft moments of inertia. Moreover, the work has also been extended blending it with the artificial potential function method for achieving autonomous capability of avoiding pointing constraints for the case of spacecraft large angle slew manoeuvres. The idea of undergoing such manoeuvres using control moment gyros to track commanded angular momentum rather than a torque command has also been studied. In this context, a gimbal position command generation algorithm has been proposed for a pyramid-type cluster of four single gimbal control moment gyros. The proposed algorithm not only avoids the saturation of the angular momentum input from the control moment gyro cluster but also exploits its maximum value deliverable by the cluster along the direction of the commanded angular momentum for the major part of the manoeuvre. In this way, it results in rapid spacecraft slew manoeuvres. The ideas proposed in the thesis have also been validated using numerical simulations and compared with results already existing in the literature

Aeronautical engineering: A special bibliography with indexes, supplement 80

This bibliography lists 277 reports, articles, and other documents introduced into the NASA scientific and technical information system in January 1977

Roving vehicle motion control Final report

Roving vehicle motion control for unmanned planetary and lunar exploratio